Bones That Look Like Other Bones: Rodent Bones VS Bird Bones

Note: As you can see, I’m no longer on hiatus! But there will be some changes to my blogging moving forward…as much as I love writing, I need to put my PhD studies first. This means that blog posts will not be weekly, but will come out a bit more inconsistently – basically whenever I have a bit of free time to blog! 

Hopefully you’ll still tune in for some weird, archaeological ramblings, even if they’re only every once in a while. Thanks to everyone who has stuck around this long!

Today’s comparative mini-post comes from a question I received from Trisha J. (thanks Trisha!),  who asked for a bit of a comparison between rodent and bird bones. Now, while I have written about both rodents and birds before, I’ve never actually compared the two in one of these posts – which is a bit of a surprise, as I totally get the confusion between them! They can look pretty similar,

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Herring gull skull (left) and brown rat skull (right)

Before we start, let me first preface this by saying we’ll be looking specifically at small bird bones – obviously, as you can see in the photo below, birds come in a wide variety of shapes and sizes! So we will be working under the impression that it’s easier to confusion small bird bones with rodent bones…unless you’re working with Rodents of Unusual Size, I guess?

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Herring gull humerus (left) and corvid humerus (right)

Unfortunately there isn’t an easy tip for differentiating between bird and rodent bones quickly – although bird bones are known for being particularly light in weight to allow for flight, rodent bones have a similar weight due to size. Thankfully, bone shapes are pretty distinct between the two. See some of the example photos below to see how each differ!

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Corvid humerus (left) and brown rat humerus (right)
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Corvid femur (left) and brown rat femur (right)
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Corvid ulna (left) and brown rat ulna (right)

If you’re dealing with bone fragments that are similar in size to either a small bird or rodent, I would highly suggest using some form of reference (photo or physical) to base your identification off of. They can certainly be quite tricky! You can also use small variations, such as the presence of “nubs” on bird ulnae, to help differentiation. Also remember that birds have bones that are not present in rodents (tibio-tarsus, furncula, etc.), so memorising their general shape will be helpful.

With skulls, if you have complete specimens, it’ll be pretty easy – the bird will usually have a beak attached!

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Corvid skull (left) and brown rat skull (right)

Of course, life isn’t fair and you will often have a skull fragment on your hands. In that case, remember that bird skulls, in particular the cranial vaults, have very rounded and bulbous skulls (see below).

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Jackdaw (bird) skull fragment

And if you’re unlucky enough to have vertebrae and ribs on your hands…well, good luck! Well, maybe at least with the ribs…vertebrae can be very tricky, especially when they’re very small. However, bird vertebrae tend to have a “body” (the thickest part of the vertebra) that curves inward and are a bit more narrow in shape.

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Corvid vertebra (left) and brown rat vertebra (right)

Have a question about zooarchaeology? Or an idea for a future blog post? Remember you can contact me through the blog by heading to my Contact page.

References

Cohen, A. and Serjeantson, D. (1996) A Manual for the Identification of  Bird Bones from Archaeological Sites. Archetype Publications Ltd.

Prehn, N. et al. (2018) Beginner’s Guide to Identifying British Mammal Bones. Natural History Museum. http://www.nhm.ac.uk/content/dam/nhmwww/take-part/identify-nature/british-mammal-bones-ID-guide.pdf

 

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Bones That Looks Like Other Bones: A MiniPost About Birds and Rabbits

I’ve been quite busy doing analysis on assemblages for my PhD project, so I don’t have much time for blogging these days. But in (belated) honour of International Rabbit Day, here’s a quick comparison of rabbits and birds!

Birds and Rabbits
Herring gull skull on the left, rabbit skull on the right

For the most part, rabbits and birds are quite distinguishable animals. I mean, one has wings and feathers and the other doesn’t – how could you mix them up?

Well…once you have just the bones, it can get tricky.

Rabbit Bird Tibias

Let’s take, for example, the tibia. Above is a photo of a bird tibia and a rabbit tibia – can you guess which is which?

They don’t look exactly alike, of course, but rabbit bones (rabbit tibia is on the bottom) have similar sharp characteristics you’d normally expect bird bones (herring gull tibia is on the top) to have.

Bird Rabbit femurs

Now this is a bit easy as the bones are marked, but you can see the similarities between the bird femur (game cock femur on the left) and the rabbit femur (on the right). Again, note the sharp edges of some of the rabbit bone that looks similar to many bird bones!

And if that isn’t confusing enough, rabbit bones tend to be just about as lightweight as bird bones!

It can be very tricky, but this is why comparative anatomy and reference collections are so important!

#FolkloreThursday – Magical Flight with Birds

My current PhD research is focused on looking at animals in ritual, so I’ll be making short blog posts examining the different ways animals are seen in cosmological contexts as part of my own contribution to the #FolkloreThursday feed on Twitter. 

Wood Pigeon
A wood pigeon skull with its ulna – note the notches on the ulna, where feathers would attach.

In my recent work with mixed assemblages involved in funerary rites, I’ve come across many bird bones. At this preliminary stage in my research, it appears that butchered birds may have been incorporated into rites performed at this site.

But why birds? What’s so special about them?

Birds, barring a few examples, have the unique ability to fly. To those in the past, this was probably acknowledged as an act emblematic of supernatural power, the ability to move from the heavens to the earth with ease. Birds were considered divine messengers, whose appearance could indicate an omen from the gods and goddesses above (Green 1992).

Shamans in various communities have been noted to adopt aspects of the bird in their work and appearance; this displays their power of “flying” from one world to the next (Eliade 1964).

Throughout later prehistoric Europe, birds continued to have an association with the mystical and the magical. Birds such as ravens and crows have been known to “talk”, which ultimately associated them with divination and prophecy (Serjeantson and Morris 2011). Birds of prey and scavenging birds were most likely incorporated into funerary rites involving excarnation, or the defleshing of a body – this, in turn, led to an association of these birds with death (Harding 2016). Wild birds appear to have been hunted, but not necessarily eaten – perhaps these birds were participants in ritualistic hunting?

Helmut of Ciumesti
This helmet from Ciumesti is an example of co-opting the bird of prey as a means of showcasing an almost otherworldly fierceness

These beliefs have been observed in various artefacts from the later prehistoric – this includes Iron Age art depicting wings, drinking vessels decorated with waterbirds, and even weaponry and armour using bird motifs (Green 1992).

Of course, these aren’t the only instances of the magical properties of birds – we see this in various myths across cultures, from Odin’s ravens to Athena’s owl. Birds continue to be associated with the magical to this day…what would Harry Potter be without Hedwig, after all?

Bird Ulna
A comparison of different birds and their ulna bones – (top to bottom) herring gull, eider duck, and magpie. Again, note the notches for feathers!

References

Eliade, M. (1964) Shamanism: Archaic Technique of Ectasy. London: Routledge & Kegan Paul Ltd.

Green, M. (1992) Animals in Celtic Life and Myth. London: Routledge.

Harding, D. W. (2016) Death and Burial in Iron Age Britain. Oxford: Oxford University Press.

Serjeantson, D. and Morris, J. (2011) Ravens and Crows in Iron Age and Roman Britain. Oxford Journal of Archaeology 30 (1), 85-107.

On Birds, or Why Light Bones Freak Me Out

Maybe this is a real “duh” moment for me, but the first time I picked up a bird bone (and a rather large one at that), I was genuinely freaked out by how light their bones are! Thinking back, of course, it seems a bit obvious why bird that fly would need relatively lighter bones, but in my defence, it is very unsettling to have a bone be so light when you’re not expecting it.

An Atlantic Herring gull skull and beak

 

One of the skills you learn going into zooarchaeology is quickly finding indicators that allow for relatively quick identifications off-hand. Of course I’m not gonna hand in a bone report made up of five second IDs, but when you’re faced with a pile of hundreds of animal bones, it does help to do a little preliminary analysis using a few indicators you know.

Anyway, here’s two general bone elements that may be helpful to know off hand for a quick ID of a bird skeleton:

The left ulna of an Atlantic Herring gull

The bird ulna is part of the “forearm” and I find that they can often be ID’ed by these bumps that are found running along the bone.

A furcula from a duck

The clavicles of a bird are fused together into an element known as the “furcula“. This is also what is often referred to as a wishbone. Given this is a unique element in birds (and some dinosaurs apparently! I don’t know much about dinosaurs and their skeletons, but I can at least identify the furcula if present – it’s a bit impressive to kids, at least), the presence of this bone should be a giveaway that you’ve got a bird on your hands.

This isn’t an extensive bird identification manual (although hey, maybe that’s a post for another day?), but again, I find that having these small little hints tucked away are handy for getting a start on IDing bones. Look for more of these kinds of posts in the future!